We request a custom built Digital Scanned Laser Light Sheet Microscope (DSLM), which will enable a broad group of investigators in Chicago to visualize proteins in live tissues and organisms with high resolution and speed and without sample damage associated with other fluorescence microscopy techniques. A major user group will be the investigators participating in at the Chicago Center for Systems Biology (CCSB) (://www.chicago-center-for-systems- biology.org/; grant P50GM081892). The Center's scientific program focuses on the dynamics of transcriptional networks on physiological, developmental and evolutionary scales. The new system will particularly enable us to generate and analyze extensive libraries of the expression networks in development, norm and disease progression. Because of the unique capabilities of this instrument, we have also received requests from groups outside The University of Chicago and we will reserve 25% time on the instrument for these users (minor user group). The DSLM is an innovative live-imaging fluorescence microscopy system developed by Dr. Stelzer's group at the European Molecular Biology Laboratory (EMBL) (Keller et al., 2008. Science, 322:1065-9). In comparison to other advanced fluorescence microscopy techniques (confocal and two-photon) the DSLM provides more than 50 times higher imaging speeds with 10 times higher signal to noise ratio, while exposing the specimens to at least two orders of magnitude less light. It presents a further improvement of a related technology, also introduced by the Stelzer group, known as Selective Plane Illumination Microscopy (SPIM) (Huisken et al., 2004. Science, 305:1007-9). The new equipment will be housed at the Institute for Genomics and Systems Biology (IGSB) (://www.igsb.org/) and will have an immediate impact on CCSB's advanced imaging platform for three important reasons. First, it would largely complement our existing confocal system coupled with a microfluidics device developed at The University of Chicago. Second, it will allow us for the first time to dynamically image fluorescently tagged transcription and other factors in model organisms (worm, fly, frog, and zebrafish) as well as in tissues and cell cultures under different physiological conditions over long periods of time, with the highest spatiotemporal resolution. Finally, the DSLM would leverage not only the CCSB research and infrastructure, but also other multiple NIH funded projects, including those presented in this application, bringing live imaging microscopy studies to the next level of speed and resolution. PUBLIC HEALTH RELEVANCE: The newly developed fluorescence Digital Scanned Laser Light Sheet Microscope (DSLM) dramatically minimizes photo damage to the specimen at the same time increasing both the speed and quality of live imaging. Such combination of features is unique to this instrument, which will enable investigators at The University of Chicago and collaborating institutions to perform in-vivo imaging experiments over long durations (e.g. several days of development)and at cellular resolution. This will greatly enhance our capabilities in cellular and developmental genomic research, particularly through visualizing and studying spatiotemporal networks of gene expression in norm and disease.